As the material of a gland packing used at, for example, a shaft sealing portion in a fluid apparatus or the like, there is known a material using, as its base material, expanded graphite excellent in compression-restoring force and sealing properties.
The gland packing of such material is made by a compression molding method of the laminate type, the die molding type, the tip molding type, the ribbon pack type, or the like. Such gland packing should be previously made in the form of a ring having an inner diameter corresponding to the outer diameter of a shaft to be sealed. Accordingly, the gland packing cannot be used for a shaft of which the outer diameter is not fit for the inner diameter of the ring-like packing. Thus, such packing lacks versatility. Further, the expanded graphite itself is poor in tensile strength and therefore fragile. This makes it difficult to take out, for replacement, such gland packing which has been mounted on a stuffing box or the like. Thus, the gland packing presents a problem in view of practical utility.
In addition, the respective types of the compression molding present the following problems.
In the laminate-type, the yield is low, leading to increase in production cost. In the die molding type and the tip molding type, gland packing is molded with the use of molds, causing the production cost to be increased. Further, such gland packing lacks versatility. The ribbon pack type presents poor workability.
The problems mentioned above may be solved by making the expanded graphite in the form of a string or braided packing, so that the string-like expanded graphite may be used as cut into a predetermined length according to the diameter of a shaft to be sealed. However, the expanded graphite itself comprises vermiform particles, each of which is expanded in the direction of the C-axis of the crystal of a graphite particle. These vermiform particles as agglomerated may be compression-molded into a sheet. However, the expanded graphite even made in such a sheet, is poor in tensile strength and therefore fragile. Accordingly, such a sheet cannot be cut into yarn suitable to make a braided body. It is therefore not possible to apply such expanded graphite to a packing which may be used as cut to a predetermined length according to the diameter of a shaft to be sealed and wound around the outer periphery thereof. The same comments apply to a braided packing.